worn out carb air mixture system?

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kdxdazz
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worn out carb air mixture system?

Post by kdxdazz »

i recently installed a chinese copy 33mm pwk and although it runs not perfect but not bad it is way better than the rb modded carb that i have been struggling to tune for 2 years now. the chinese copy carb actually idles where as i could never get the rb carb to idle. on closer inspection the mixture screws although identical sit completely differently when in the carb ,shown in the photos is exactly 1.5 turns out on the mixture screw. i have a feeling that the rb carb mixture system is worn out and really 1.5 turns out is starting from zero. would anybody be able to post a photo of their mixture screw at exactly 1.5 turns out so i can compare and prove my theory. cheers guys
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rb carb
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1999 KDX220SR (KDX220-B5)
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Goat
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Re: worn out carb air mixture system?

Post by Goat »

This is a 35mm PWK AS, at 1.5 turns.
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Re: worn out carb air mixture system?

Post by Goat »

Try again on pic.
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Re: worn out carb air mixture system?

Post by Goat »

Maybe same screw. I can measure if it helps test your theory.
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kdxdazz
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Re: worn out carb air mixture system?

Post by kdxdazz »

thankyou goat that helps alot although it looks like my theory is completely wrong, yours is almost the same as my rb carb. i noticed your carb also has the notch cut out where the needle is, is yours an RB carb or is that standard on airstrykers
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Re: worn out carb air mixture system?

Post by Goat »

The pic is from a stock PWK.

https://www.jetsrus.com/individual_part ... 60_su.html

I have just installed an RB AS, so the old one is on the shelf.
So far my RB does not idle, either. But I love the way it runs, otherwise.
Held its own with KTM 300 & Husky 350, on Sat.
But I do think they were just letting me tag along.
I have not followed the RB fine tuning instructions yet
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Re: worn out carb air mixture system?

Post by kdxdazz »

Having a bike that doesn't idle is a big deal, what jetting are you running.
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Re: worn out carb air mixture system?

Post by Goat »

I am running:
PJ - 40
MJ - 152
Needle - CEK/3
I agree, I do need to investigate further.
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Re: worn out carb air mixture system?

Post by kdxdazz »

CEK is such a rich needle. I will solder the straight diameter on mine to make it a ceq
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Re: worn out carb air mixture system?

Post by Goat »

My reading so far seems to imply that CEK or DEK should work well with the RB carb mod. But I am still about 10 yrs behind in the posts.
My idle issue may be as simple as I tried to set it before bike was fully warmed up. If I don’t wuss out for cold or frost on the road, I’ll give it mother shot tomorrow.
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Re: worn out carb air mixture system?

Post by kdxdazz »

I've read lots of posts about the CEK being too rich at idle, not sure what kind of gasoline you have in America but as a test you can try running 100 percent gasoline, 95 e10, 91 e10 in that order, first being the richest and last being the leanest. If it gradually runs better you will no too rich
1999 KDX220SR (KDX220-B5)
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